How to reduce server response time
When the server takes over 600 ms to answer, nothing else can start. Caching, a faster host or a CDN fix most cases.
Step by step, with screenshots: How to reduce TTFB: fix a slow server response time →
Check your own site
Runs these 3 checks and the other 190, free, in about 45 seconds.
Or run only this check with the free Web hosting speed test or the free TTFB test.
What it is
Server response time is how long your server takes to produce a page's HTML after the request reaches it. It is the part of Time to First Byte you control on the server: running the CMS, querying the database and rendering the template, without the visitor's network time.
Lighthouse flags a server response slower than 600 ms as "Reduce initial server response time", and getReport uses the same limit; a cached page on decent hosting usually answers in under 200 ms. Once getReport has checked 50 sites on your host, it also compares your first byte with theirs, so you can tell a slow host from a slow site.
What a passing site looks like
- Server response time: passeswarning · −2 ptseffort M
- Speed against other sites on your host: passesinfo onlyeffort M
- Every crawled page answered in under 0.8 sinfo onlyeffort M
1. Server response time
Why it matters. Lighthouse flags a first byte slower than 600 ms. Caching and hosting fix this for most CMS sites.
- Enable full-page caching (WordPress: WP Rocket, LiteSpeed Cache, WP Super Cache; or your host's server cache).
- Use a CDN and keep database queries out of the request path.
2. Speed against other sites on your host
Why it matters. Comparing your server with other sites on the same host shows where a slow first byte comes from. When most sites on the host answer faster, the host is not the limit; slow plugins, missing page caching or an undersized plan usually are. The numbers are anonymous, from sites we checked, and appear only once a host has 50 sites.
- Turn on full-page caching first; it removes most of the server's work for repeat visits.
- Profile the slowest plugins or database queries (Query Monitor on WordPress) and remove or replace them.
- If the site is already cached and lean, ask the host for a larger plan or move to a faster one.
3. Slowest pages
Why it matters. Nothing appears until the server answers, so a slow first byte delays everything that follows. web.dev counts up to 0.8 s as good. These are single measurements from our crawler, so treat them as a list of pages to test again.
- Test the pages listed with the speed test; if they stay slow, look at what the server does for them, such as uncached database queries or slow plugins.
- Turn on full-page caching so repeat visits do not rebuild the page.
Questions people ask
What is initial server response time?
It is how long your server takes to answer the browser's request for the HTML document, as measured by Lighthouse, which flags it above 600 ms. It is the server's share of Time to First Byte, without the network setup before it, and depends on your hosting, whether the page is served from a cache, and how much work the CMS does to build each page.
How do I reduce server response time in WordPress?
Install a page caching plugin, or use your host's built-in cache, so most visitors get a ready-made copy. Update PHP to a supported version, remove plugins that run heavy database queries on every page, and use an object cache if your host offers Redis or Memcached. If response time stays high with caching on, the hosting plan or the host is usually the limit.
What is a good server response time?
Under 600 ms passes Lighthouse, and under 200 ms is good for a cached page. Google's target for the full Time to First Byte, which includes the visitor's network, is 800 ms at the 75th percentile. Uncached pages such as the cart, checkout and search results will be slower; keep them under 1 s if you can.
How do I check server response time?
Run a getReport check, which shows the server response time from a Lighthouse test and, once enough sites on your host have been checked, how it compares with them. In Chrome DevTools, select the page request in the Network panel and read "Waiting for server response" under Timing. Test a few times and different page types, as cached and uncached pages differ a lot.
Does server response time affect SEO?
Indirectly. Slow responses delay Largest Contentful Paint, a Core Web Vital, and Google crawls fewer pages per day from servers that respond slowly or return errors. For a small site that rarely matters; for a large shop with thousands of products, a faster server helps new pages and price changes get crawled sooner.